TSLP as a therapeutic target

Although T helper 2 (TH2) cells mediate immunity against extracellular parasites, they also promote allergic inflammation. The cytokine interleukin-4 (IL-4), which is produced by TH2 cells, is also required for their differentiation. Noting that the cytokine TSLP is implicated in the pathogenesis of TH2 cell–associated allergic disorders, Rochman et al. investigated its role in TH2 cell differentiation. They found that TH2 cells that differentiated in the presence of TSLP and IL-4 produced increased amounts of cytokines and were more pathogenic compared to TH2 cells differentiated in the presence of IL-4 alone. Mice that received CD4+ T cells deficient in the TSLP receptor had reduced allergic responses compared to those that received wild-type cells. Given that pediatric asthma patients had enhanced TH2 cytokine production compared to that of healthy controls, these data suggest that TSLP may be a therapeutic target in allergic diseases.